Traditionally manufactured with powder compaction or injection moulding, Fabrice Bernier and Jean-Michel Lamarre believe they have found a potentially revolutionary method, which reduces cost and provides greater freedom in the design process. The magnets in an electric motor are essential components, providing rotary mechanical movement to ensure the motor runs. Typically, these magnets must be fabricated, then shaped and then assembled. Bernier and Lamarre, with their cold spray technique, can do this all at once.

In the cold spray process, fine powder is accelerated in a high-velocity compressed gas jet, building up layer by layer to form a part. An industrial robot controls the process, performing rapid and precise 3D movements, which enables complex shapes to be created. Such is the speed of the process, several kilograms of magnets can be printed every hour. The NRC also reports excellent mechanical and thermal properties, achieved thanks in large part to the high velocities used in the deposition of the material and the absence of polymer in the material matrix. Moreover, the NRC says the adhesion of the magnetic material to the surface of the part is ‘exceptional’, since neither glue nor assembly is used. The resulting intrinsic mechanical properties are said to be ‘far superior’ to conventional magnets, while the components are also easier to machine when manufactured with cold spray.

Jacques Frenette

NRC researchers Jean-Michel Lamarre and Fabrice Bernier reveal a product made using their new magnet manufacturing technology.

It is suggested that this alternative method of developing magnets for electric motors could be of great use in the automotive sector, or applied in key applications like magnetic cooling, wind turbines and telecommunication devices.

“This technology will allow the creation of more compact, better performing motors for the future and could pave the way for building entire motors using cold spray technology, offering significant advantages such as cost reduction, better thermal management and more complex geometries and functionalities,” says Bernier.

Bernier and Lamarre have successfully tested several prototypes using the process, and are now exploring other ways to harness the cold spray technique to enhance motor designs. The pair are also looking to develop soft magnetic materials, to ensure a comprehensive range of resources for the additive manufacture of the magnetic components.